Objectives: Appropriately designed and adequately controlled quality control tests are a cornerstone of the pertussis vaccine regulatory program. Whole-cell pertussis vaccines have been adequately controlled by potency and toxicity tests defined by Federal Regulation; the Laboratory is responsible for maintenance of Standards for these tests. Acellular pertussis vaccines, on the other hand, represent a new product class for which standardized and internationally-accepted methods for assessment of product purity, potency and safety are under active development. Because most manufacturers of acellular pertussis vaccines are expected to market internationally, international standardization of methods and reagents is highly deisrable. With respect to quality control of pertussis vaccines, the Laboratory: a) Develops and evaluates new tests to assess the safety, purity, and potency of acellular pertussis vaccines. b) Prepares and maintains standard materials and other reagents for the control testing of pertussis vaccines. c) Standardized and performs the toxicity and immunogenicity tests employed for currently licensed whole-cell and acellular pertussis vaccines. FY97 activities: 1. In the past year, the Laboratory performed 28 potency and 25 toxicity tests on vaccines containing a whole-cell pertussis component and 32 potency and 25 toxicity tests on vaccines containing an acellular pertussis component. 2. Continued evaluation of the mouse imunogenicity test used as the lot release potency tests for acellular pertussis vaccines and continued ongoing collaborative studies with all manufacturers pursuing US-licensure to assess the inter-laboratory reproducibility of the proposed immunogenicity assay.3. Continued ongoing program to monitor CBER and manufacturer potency testing data of lots of whole-cell and acellular pertussis vaccines submitted for release. Data are analyzed to evaluate inter-laboratory reproducibility and to examine for temporal trends.4. Two individuals from the laboratory were consultation committee members and wrote substantial portions of the first draft of the WHO Guidelines for the Production and Control of Acellular Pertussis Component of Monovalent or Combined Vaccines. Ongoing review led to the preparation of the final draft which has been submitted for action by the WHO Expert Committee on Biological Standardization.